Abstract:A neutral multi-return leaching experiment was carried out on a sandstone-type uranium ore in Xinjiang under different O2 dose conditions. The results show that neutral leaching efficiency is poor for the interest ore. Peak of uranium concentration is generally lower than 20 mg/L, and uranium recoveries are only 35.36%-41.85 % under L/S of 25.2; Leaching intensity positively correlate with HCO3- concentration significantly during early stage of leaching and the leached uranium is dominated by hexavalent uranium. Effect of O2 on uranium dissolution had been shown after hexavalent uranium in the ore exhausted. Difference of leaching results between test with O2 and without O2 is obvious. However, it is noteworthy that effect of O2 with different doses between 30 mg/L and 200 mg/L is not significant. Higher pH is beneficial for formation of uranyl dicarbonate and uranyl tricarbonate, and lowering redox critical potential of uranium oxidizing, but it is also needed to avoid high pH value which may lead to calcium carbonate precipitation. Maintaining more than 800 mg/L of HCO3- in lixivant solution and 10-20 mg/L of dissolved oxygen in pregnant solution is recommended for neutral in-situ leaching process of that deposit.